Made of safe and eco-friendly PVC material. High quality for durable and reusable use. Safe and harmless with high temperature resistance. Fill and use with water injection design. High sealing and anti-leaking, no water leaks out. Lightweight for portable carry. Low heat dissipation for long-time warming. The insulation effect is very good. They are perfect for home and daily use. Imprint your exclusive logo, everyone who uses it will know your company name.